Typing impression control for typewriters



Feb. 12, 1963 R. E. COLEMAN ETAL TYPING IMPRESSION CONTROL FOR TYPEWRITERS Filed July 11, 1960 ATTORNEY Feb. 12, 1963V R. E. COLEMAN ETAL 3,077,255 TYRING IMPRESSION CONTROL FOR TYREWRITERS Filed July 11, 1960 5 Sheets-Sheet 2 RUSSELL E. caf/WAN BY 5v5/R7 Gum/:150m

ATTR/VEY: R'

Feb. 12, 1963 R. E. COLEMAN ETAL 3,077,255

TYPING IMPRESSION CONTROL FOR vTYPEWRITERS Filed July 11. 1960 3 Sheets-Sheet 3 FIGA :mlrl

FIGS

INVENTORSV @0:15a E, 60mm/v ,5a/mr s. /m/:fLso/v ATTORNEY United States Patent Viice 3,077,255 TYPING IMPRESSIGN CONTROL FR TYPEWRITERS Russell E. Coleman, Elmira, N .Y., and Evert G. Israelson,

Rowayton, Conn., assignors to Sperry Rand Corporation, New York, N.Y., a corporation of Delaware Filed July 11, 1960, Ser. No. 41,854 13 Claims. (Cl. 197-17) Th.s invention relates to typing impression controls for typewriters and like machines, and more particularly to a mechanism for controlling the force of the printing impact on the platen and the ribbon by individual adjustment of any type bar in either lower or upper case in order to obtain typing of uniform appearance.

Normally, typing operations call for the ink impregnated in a typewriter ribbon to be transferred to paper through the ribbon upon the impact of a type bar against the platen. The ink in the ribbon is readily transferable and the paper carried in the typewriter carriage can be imprinted in varying degrees of intensity as regulated by the force of impact of the type hars. It is necessary for the applied pressure of each type bar, therefore, to be adjustable in order to produce uniform typing impres sions. Vario-us devices have been used for adjusting the force of the impact of the type on the platen, but many of these devices have been too complex and expensive, particularly-where pressure variations are to be adjusted in upper case as well as in lower case, and retaining this adjustment during subsequent typing has proven, in many instances, to be diilicult.

VOne object of Athe invention is to provide an impact impression control for typewriters and like machines, the adjustment of which can be readily maintained.

Another object of thev invention is to provide means for controlling the force of impression of each individual type bar.

Another object of the invention is to provide a manually adjustable impact impression control operable in both Eupper and lowercase positions of the type.

Still another object of the invention is to provide interrelated mechanisms for case shifting andimpression control in a typewriter with independent upper and lower case impact adjustment.

Further objects and advantages relating to details and novelties of construction and operation will become apparent from the detailed description and accompanying drawings forming a part of this specification, in which:

FIG. l is a vertical view in section through part of a power typewriter illustrating an impact impression adjusting mechanism as applied to a type action,

FIG. 2 is a view in side elevation with portions shown partly in section illustrating the relationship of the impact adjusting mechanism shown in FIG. l, to the case shifting linkage,

FIG. 3 is a side view of a case shift mechanism used in connection with the invention,

FIG. 4 is an enlarged view of part of FIG. 3 showing another position of the shift mechanism,

FIG. 5 is a section on line 5-5 of FIG. 4,

FIG. 6 is a vertical section taken on the line 6--6 of FIG. 2 looking from the front of a typewriter and illustrating an individual type bar adjusting mechanism,

FIG. 7 is a top plan view of one end of the mechanism shown in FIGURE 6,

FIG. 8 is a section taken on the line 8 8 of FIG. 6 illustrating the manner in which a limit strip carrier bar is anchored to a bell crank pivot block against arcuate motion,

' FIG. 9 is a fragmentary part of the mechanism shown in FIG. 1 and illustrating another form of impact adjustment means, and

FIG. 10 is a view similar to FIG. 9 showing the parts in another operating position.

, Referring to the drawings in detail and in particular to PIG. l, a conventional power operated type action 10 is shown which coacts with a power roller 11, journalled in the opposite side frames 12, FIG. 6, of a typewriter, and comprising a power cam 13, rotatably mounted on a power arm 14, to engage the roller 1l. The power arm 14 is connected by suitable linkage in the well known manner to a character key of the keyboard as shown in FIG. 2A of Patent 2,919,007 t-o F. W. Schremp, granted December 29, 1959. All of the type actions are substantially similar in design and operation, and hence only a single action will be hereinafter referred to. The rearwardly extending extremity of the power arm 14 is pivoted to a camming lever 16 which in turn is pivoted as at 15 to the upper end of a vertically disposed impact control crank 15. A roller 16 on the end of the lever 16 normally engages the angular camming edge of a type bar bell crank lever 17 pivoted on a wire 18 in the comb portion of a bell crank pivot block 19. The bell crank lever 17 is provided with a depending arm 20 which is normally urged by a spring 21 against a comb stop plate 22, FIG. l. A wire link 23 pivotally connects the upper end of the bell crank lever 17 to a type `'bar 24, pivoted as at 25 in an arcuate type segment or type basket 26. This segment, slidably disposed between the frames 12, at an angle of several degrees from the vertical, is lowered by the depression of the .usual case shift key on the keyboard for placing the type bars in position to print upper case characters on a paper held in the usual manner against a platen 27, said action lto be more fully explained hereinafter in conjunction with the type impact adjusting means.

A limit strip carrier bar 36 disposed below the power roller 11 and extending virtually the width of the typewriter is swingably suspended at opposite ends by shouldered screws 31 from the inner faces of levers 32 and 33. Said levers pivot on a rod 34 which is rigidly mounted in and extends between the side frames 12. A limit strip bail 35 extending along the top,.longitudinally of the center thereof and substantially the length of the carrier bar 3d has its two ends or legs 36 and 37 bent at angles of to pass loosely through holes 38 in the carrier bar, FIGS. 2 and 6. The holes 38 are formed by, and are in axial alignment with, counter bored cavities 40 which penetrate the bar to a maximum depth that will define an end wall for the cavity of minimum thickness.

The bored cavities 40 are of suitable diameter, FIG. 2, to permit the legs 36 and 37 of the bail 35 to be swung freely and to be limited in swinging movement by the entrance rim of the counter bores at the underside of said carrier bar 30.

The legs 36 and 37 of the bail 35 extend below the bar 30 and through holes 41, in a limit strip 44, said holes being of greater diameter than the bail. Each leg of the bail is provided with a xed abutment washer 42 against which springs 43, on said legs, bear in order to yieldably maintain the limit strip 44 against the lower surface of the carrier bar 30. One leg 36 of the bail 3S terminates in a right angled crank portion 45 and is pivotally secured to one end of a bail rocker 46, the other end of which is loosely mounted on a case shift bell crank 47, pivoted as at 48 to a fixed point in the machine. A rearwardly extending arm 49 of the crank 47 is urged upwardly by spring 50, and maintained in riding contact with the lower arcuate edge or surface of a vertically movable segment shaft cam arm 51, FIGS. l, 2 and 3. v

The impact control crank 15, corresponding to each key action, posed approximately midway between the power roll 11 and the pivot block 19, and is formed with a right-angled Patented ree. 12, 1963- is shaped to provide a vertical leg 52 dis-V base portion 53 which extends horizontally beneath and parallel to the limit strip 44 and at a predetermined distance therefrom. Each base member 53 provides staggered semi-tubular sections 54, internally threaded to aC- commodate'lower case and upper case adjusting screws 55 and 56, respectively. The adjusting screws after having been set are likely to turn from constantly hitting the limit strip 44 with every action of the power arm during typing, thereby throwing off the adjustment of impact sought. In order to overcome this condition we provide a small holding block 57 of resilient material, preferably nylon, drilled and tapped with close fitting screw holes for each set of lower and upper case screws, which block is forced and held against the underside of each base member 53 to more securely retain the screws in their adjusted positions.

In order to maintain the leg portions S2 of the cranks evenly spaced from each other and to prohibit any lateral sway, each leg is disposed in a slot in a comb bracket 58. A spring 60, secured at one end to an ear of each leg 52 is anchored at its opposite `end to a suitably fixed part of the machine and resiliently forces the legs 52 against the inner edges of the slots in the comb 58. By its downward pull each spring 60 constantly urges the entire unit composed of the impact control crank 15 and the power arm 14 downwardly toward the power roll 11 and toward a stop bar such as the one designated at 99 in FIG. 7 of Patent 2,638,199, granted May 12, 1953, to F. W. Schremp, but which is not necessary in the use of the present invention.

Varying -degrees of force are necessary to throw a. type bar against the ribbon as the number of carbon copies changes. For example, a minimum of force iS applied through the power mechanism to drive the type bar in single sheet copy work compared to a maximum of force applied when nine or ten carbon copies are to be reproduced. To meet these conditions we provide a. combination impression control and impact adjustment so that the striking power of a type'bar may be closely regulated after adjustment regardless of the force required in accordance with the work to be accomplished. In FIG. 1 a type bar impression control is shown which comprises a knurled hand wheel 65, mounted for free rotation on a stud shaft 66 which projects from a side frame ofthe machine. The wheel 65 has formed integrally therewith an impact control cam 67 provided on its periphery with arcuate recesses for engagement by a roller 68 on one end of a crank lever 70 suitably pivoted on the frame as at 71. The opposite end of the lever 70 is connected by a link 72 with the free end of lever 32. It will be evident that as the hand wheel 65 is turned in either clockwise or counterclockwise direction the carrier bar 30, held by levers 32 and 33 along with the limit strip 44, will be lifted away from or lowered tow-ards the adjustment screws 55, 56 to adjust the force with which the type bars strike the paper in printing operation by changing the driving effect of the roller 16.

The carrier bar 30 must be retained in a horizontal plane as it is moved vertically by the studs 31, which have a slight arcuate motion due to the rocking of the levers 32 and 33 around rod 34, so that the operation afforded by the screws 55 and 56 will not be altered. In FIGS. 1, 6 and 8, means are shown for positively retaining the carrier bar 30 in horizontal position which includes a plate 73 fixed to the underside of the pivot block 19 and extending forwardly to a position below one end of the carrier bar 30. A stud screw 74 is threaded into a tapped hole in the carrier bar 30 and extends downwardly to engage a slot 75 in the adjacent edge of the plate 73. The stud screw 74 being threaded into the threaded hole in the bar 30 permits suitable -adjustment of the bar 30 with respect to the plate 73. No matter in what direction the levers 32 and 33 are swung the bar 30 will remain horizontal by having rotational relation with the studs 31 counter to the direction of lever swing thereby maintaining the Iadjustment setting between the screws 55 and 56 and the limit strip 44.

Since the adjustment made possible by this invention is related to lower and upper case type bar impact, provision is made to synchronously Shift the limit strip 44 in order to align it with the proper screw 55 or 56 as either case is selected. When a change from lower case to upper case is desired, a shift key on the keyboard is depressed to lower the type bar segment or basket 26 so that the upper face of the type bar will make an upper case character impression. Referring specifically to FIGS. l, 2 and 3 a continuously rotating case shift shaft 80, dispo-sed below the vertically movable type segment 26, is journalled in the side frames and driven through suitable gearing from the drive motor, not shown. The case shift shaft has keyed thereto adjacent its left extremity a ratchet gear 81. Directly adjacent said ratchet gear 81, a cam 82 is eccentrically mounted for free movement on the shaft 80 and has pivoted on the face thereof adjacent said ratchet 81 a pawl or dog 83, biased by a spring 84 for engagement with the teeth of the ratchet. Said cam S2 rotates in a suitable opening in the shift cam arm 51 so that as the cam 82 rotates about the shift shaft 80 the arm 51 will oscillate vertically to raise or lower the type basket 26 depending upon the operation of said ratchet gear 81.

The pawl or dog 83 has a tail 86 which is arranged to engage the outside of an ear 87 formed at the free end of an upper bell crank 88 of a parallel detent link arrangement which includes a lower lever 89 also having at its free end an ear or tab 91 the inside of which may be engaged by the vtail 86 of the pawl 83 as seen in FIG. 4, wherein it will be evident that a blocking pin 92 limits the rotary movement of the pawl in one direction and also forms a positive lock stop for rotation of the shift cam at opposite extremes of its movement in case shift operations. The ends of bell crank 88 and lever 89 are joined by a link 93 which insu-res mutual swinging movement of the parts when a pull is exerted on the tie rod 94 by operation of the shift lever 96 which is provided with a shift key finger piece 97 and a latch key 98 for engagement with -a latch strip 99 to hold the shift lever 96 in selected case position. The normal position of the parts is `as depicted in FIG. 3 Where lower case typing s done. The dog 83 is held out of engagement with the constantly revolving ratchet gear '81 until the shift key 97 is operated to pull on tie-rod 94 to cause bell crank 88 to release the pawl 83 which engages the ratchet gear and transmits rotary motion of the shaft 80 to the shift cam 82. The latter rotates one-half a turn to raise the type basket 26 at which time the parts are in the position shown in FIG. 4 and are so held by reason of the ear 91 having moved into the path of the tail 86 of the pawl to free the latter from the ratchet gear and halt the rotary movement of the cam 82. When the shift lever 96 is released a suitable spring will move it to normal or FIG. 3 position.

In FIGS. 9 and 10 use is made of an Iadjusting means which includes a case shift bell crank 101 similar tto bell crank 47 (FIG. 1) which is actuated by the vertical case shift movement of the shift cam arm 51 to adjust a bail rocker link 102, similar to link 46. The link 102 is pivoted to the lower end of a rocker yarm 103 secured to the end of a case shift control shaft 104 which is seated in a longitudinal recess 106 in the bell crank pivot block 107 which corresponds to the block 19 previouslyy referred to.n The shaft 104 is slotted or undercut as at 108 substantially half its diameter to provide a camming action for the impact control ycranks 109, the legs 111 of which are biased for contact with the shaft 104 by individual springs 112. These cranks are the same as the cranks 52 previously explained `and are formed at their lower ends with a base portion 113 having threaded sleeves 114 in which are adjustably mounted upper and' lower case screws 116 and 117, respectively. These 'screws are arranged to coact with upper and lower case Isteps 118 and 119respectively, formed on the bottom of a limit bar 121, suitably supported at its opposite ends in the frames of the machine.- The upper end of each crank 109` is pivoted to thecamming lever 16 of the power mechanism so that the force of the impact is closely controlled by the individual adjustment of the screws 116 and 117.

It is evident that an upward lift of the power arm 14 will lift the lever 16 which acting as a lever of the third class will pull up on crank 15 until its selected screw 56 or 57 limits on the limit strip 44 of the carrier bar 30 and then the lifting action of lever 16 will operate the bell crank 17. The difference in time that the power is applied to the type bar as controlled by the movement of crank 15 determines the adjust-ment of impact.

While we have described what we vconsider to be a highly desirable embodiment of our invention, it is obvi` ous that changes in form could be made without departing from the spirit of the invention and therefore we do not limit ourselves to the exact form herein shown or described nor to anything less than the whole of our invention as hereinbefore set forth, and as hereinafter claimed.

What we claim is:

1. In a writing machine having type bar operating means and a movable power ar-m; a printing impression control comprising impact control means, lever means fulcrumed on-and actuated by said power arm for operating said type bar operating means and said impact control means, and limit means for arresting the operation of said impact control means for modifying the operation of said type bar operating means through said lever means.

2. In a writing machine having type bar operating means including a movable power arm; a printing impression control comprising impact control means, lever means fulcrumed on said power arm for rst moving said impact control means and then said type bar operating means, and limit means for arresting the movement of said impact control means and transferring the operation of said lever means to said type bar operating means.

3. A writing machine as set forth in claim 2' in which said impact control means includes upper and lower case stop means adjustable for varying engagement with said limit means.

4. A writing machine as set forth in claim 2 in which said impact control means includes upper and lower case stop means and means for adjusting said limit means for engagement by said stop means to selectively control upper and lower case printing.

5. In a writing machine including type bar operating means and movable power arm means for actuating said type bar operating means, a printing impression control including vertically movable type bar impact control means, lever means fulcrumed on and operated by said power arm means for actuating said type bar operating means and said impact control means, limit means for arresting the vertical movement of said impact control means, and means coacting with said impact control means and the limit means for adjusting the vertical movement of said impact con-trol means for varying the operation of said type Abar operating means through said lever means.

6. In a writing machine having a plurality of type bar operating means and a movable power arm for each of said type bar operating means; a printing impression control comprising an impact control including lever means fulcrumed on and operate-d by each power arm for operating each type bar operating means and vertically movable crank means on each of said lever means, limit means for arresting the movement of all of said crank swinging said impact control means to place said adjustaadjusting the movement thereof in relation to said limit means.

apt/'7,255

7. A writing machine as set forth in claim 6 including means for conditioning each of said crank meansV for upper and lower case operation.

8. A Writing machine as set forth in claim 6 including means for adjusting said limit means to vary the movement of said crank means and control the impact of the type bars actuated by said type bar operating means.

9. In a writing machine having type bar operating means including movable power arm means and case shift means; a printing impression control comprising a type bar impact control means, lever means fulcrumed on said power arm means for first moving said type bar impact control means and then said type operating means, limit means for arresting the movement .of said impact control means and transferring the operation of said lever means to said type bar operating means, upper and lower case step means on said limit means, and means controlled by said case shift means for moving said impact control means for selected case shift relation with said step means.

l0. In a writing machine including type bar operating means and movable power arm means, a printing irripression control including impact adjusting means, type bar impact control means and lever means fulcrumed on said power arm means for actuating said type bar operating means and said impact control means, limit means for arresting the operation of said impact control means whereby the actuation of said type bar operating means is continued through said lever means, and means controlled by said impact adjusting means for moving said limit means with respect to said impact control means for simultaneously varying the operation of said type bar operating means.

11. A writing machine as set forth in claim l0, in which each of said type bar impact control means includes means adjustable with respect to said limit means for varying the operation of each type bar operating means.

l2. A writing machine as set forth in claim 9 including means in said impact control means adjustable with respect to said limit means for varying the operation of each type bar operating means in lower and upper case position of said case shift means.

13. In a writing machine having case shift means, and type bar operating means including a movable power arm; a printing impression control comprising impact control means, lever means fulcrumed on and actuated by said power arm for operating said type bar operating means and said impact control means, and limit means for arresting the operation of said impact control means for modifying the operation of said type bar operating means through said lever means.

14. A writing machine as set forth in claim 13 in which said limit means comprises a carrier bar, a limit strip, bail means for holding said strip longitudinally of the bottom of said bar, and limit strip adjusting means including an adjusting cam for moving said bar vertically for defining different limits for operation of said impact control means, said limit strip adjusting means coacting with the case shift means to adjust the position of the limit strip upon operating of the case shift means.

15. In a writing machine having case shift means and type bar operating means including a movable power arm; a printing impression control comprising impact control means, lever means fulcrumed on said power arm for first lifting said impact control means and then actuating said type bar operating means, limit: means presenting a stepped surface representing upper and lower caes, means adjustable in said impact control means for engaging the stepped surface of the limit means to arrest a rising movement of said impact control means and slotted shaft means operated by said case shift means for swinging said impact control means to place said adjustable means in selected relation to the steps of said limit means.

16. In a writing machine including type baropei'ating means and movable power arm means; a printing impression control comprising type bar impact control means including upper and lower case stop means, lever means fulcrumed on said power arm means for actuating said type Ibar operating means and said impact control means, limit means for arresting the operation of said impact control means whereby the actuation of said type bar operating means -is continued through said lever means, and means for adjusting said limit means for movement toward and away from said limit stop means.

17. In a writing machine including type bar operating means and movable power arm means, a printing impression control comprising type bar impact control means including upper and lower case `stop means, lever means fulcrfurned on said power arm meanslfor actuating said ty-pe -bar operating means and said impact control means, limit means for arresting the operation of said impact control means whereby the actuation of said type bar operating means is continued through said lever 2 means, and means for adjusting said impact control means for selective engagement with the limit means of `said upper and llower case istop means.

1S. In a writing machine including type bar operating means, case shift means, and movable power arm means; a printing impression control comprising type bar impact control means, lever means fulcrumed on said power arm means for actuating said type bar operating means and said impact control means, carrier bar means, alimit strip slidable laterally of said carrier bar means for arresting the operation of said impact control means whereiby the actuation of said type bar operating means is continued through said lever means, and means controlled by the :case shift means for moving said limit strip.

References Cited in the lfile of this patent UNITED STATES PATENTS 2,796,966 Toeppen June 25, 1957 2,818,151 Yaeger Dec. 3l, 1957- 2,89'1,650 Ascoli June 23, 1959 UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3,077,255 February l2, 1963 Russell E. Coleman et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 73, strike out "swinging said impact control means to place said adjusta" and insert instead means and means on each of said crank means for Signed and sealed this 25th day of February 1964.

(SEAL) fittest:

ERNEST W. SWIDER EDWIN L. REYNOLDS Altesting Officer Ac ing Commissioner of Patents 

1. IN A WRITING MACHINE HAVING TYPE BAR OPERATING MEANS AND A MOVABLE POWER ARM; A PRINTING IMPRESSION CONTROL COMPRISING IMPACT CONTROL MEANS, LEVER MEANS FULCRUMED ON AND ACTUATED BY SAID POWER ARM FOR OPERATING SAID TYPE BAR OPERATING MEANS AND SAID IMPACT CONTROL MEANS, AND LIMIT MEANS FOR ARRESTING THE OPERATION OF SAID IMPACT CONTROL MEANS FOR MODIFYING THE 